Boring-bar.



H. AUSTIN.

BORING BAR.

APPLICATION min Aus.21.191s.

1,241,973. Patentedsept. 25, 1917.

HERBERT AusrIN, oF'BRoi/rsenovn, ENGLAND.

BORING-BAR.

To all whom it may concern.'

Be itknown that I, HERBERT AUSTIN, a

subject vof the King of Great Britain, and

residing at Bromsgrove, in the county of lorcester7 England, engineer, have invented certain new and useful Improvements in Boring-Bars, of which the following is a specification. g f `This invention relates to the type of boring bar in which a bar (hereinafter termed the guide bar,vwhen such is necessary to distinguish it from the complete 'boring bar), which passes through the interior which is to be bored, is surrounded by a sleeve or the like which carries the cutting tool in a manner which allows the tool to move out inrelation to the sleeve, the guide bar being formed with asurface which acts as a vformer andinsures that as the sleeve is moved k.endwise inrelation to the guide bar the cutting edgevof the tool will at any point of its travel; be at the required distance from the axis of the boring bar to cutthe interior which is being bored to the required diameter at such point;y and has for its object certain improvements therein. A y

According to this invention the Vtool is pivotally connected withthe sleeve or lthe like, andin-practice it is convenient to fix the tool in a tooleholder and to pivot the toolholder to the sleeve land though the tool or tool holder would necessarily press against the surface of the guide bar while the tool is cutting, it is pressed against such surface by means Of a spring to insure that it will be inV proper position when it is being moved valong to connnence a cut and will remain in such position even though it may have to pass over a chambered kportion of the interior which it is used to bore; and, by the use of such spring it is insured that the tool will be. prevented from waggling-vwhen theboring bar is being carried about.

If aboring bar, of the type defined in the vopening paragraph hereof, is intended to be used for boring an interior of comparatively small diameter, the portionof the guide bar along which the sleeve is Vslidable may be eccentric to the truegaxisl ofthe complete appliance, in which case, for thesake of strength, vthe vsleeve .also mayv be eccentric to such axis, but inthe opposite direction to the eccentricity Aof such portion of the guide In order that the invention may be clearly understood, I will now describe a, convenient Specification of Letters Patent.

f Application filed August 21, 1916. Serial No. 116,011.

application of the same as applied, by way' of example, to boring any explosive shell.

v, Of these .drawingszy l Figure 1 represents, mainly in sectional plan, ya boring bar constructed according to this invention, in .positionvwithin an explosive shell body.' l

' Fig.2 is a detached viewof the boring bar as seenlooking in the direction of the arrow, Fig. l.` y

Fig. k3 is a transverse sectionl through the boring bar, taken in the plane indicated by line 8 3 of Fig. l.

Fig. 4 is a-transverse section through the boring bar, taken in the plane indicated by line of Fig. 2; y

Figi. 5k shows, in side elevation, means of securing the forward end 'of the guide ,bar when the boring bar is in use, and

lF ig. 6 represents an end elevation looking toward the right of Fig. 5. Y .j

A is the explosive shell. B is a guide bar forming one of the main members of the boring bar. C is a sleevek which is slidable along the bar B. D is the tool-holder, and E the cutting tool. The shell A, bar B, and sleeve C, are shown to have a considerable portion of their rearl ends broken away, for convenience of illustration. In this instance, .the bar being usedV to bore an interior of somewhat small diameter, the portion of the bar along which the sleeve C is slidable is yshown to be eccentric to the forward end B of the bar which passes axially through theforward end of the shell. In order to insure Lthe necessary strength of the'sleeve (which is. arranged within the somewhat confined space shown) the sleeve also is made yeccentricbut in the opposite direction to the eccentricity of the portion B of the guide bar, as is clearly shown by Figs. 3 and 4. A key-way b is formed in the surface of the barB, and a keyv 6 of the sleeve C isA slidable within the key-way, whereby while the sleeve can be moved endwise of the bar it cannot turn in relation thereto. Preferably, the guide bar B is fixed and the `shell revolves, whereby the conoidal portion of ythe shell may be turned while the interior ofthe shell is `being bored;V but obviously, this is not essential, .as the boring bar might revolve and the shell be fixed.v For the sakeof deliniteness in description I will assume that the bar B is lixed. The tool-holder I) is pivoted by means of a pin vo between the sides of a slot c which is formed through the wall of the forward end of the sleeve C. Along one side of the portion of the bar B along ,which v the sleeve C is slidable is a surface 52, '63,of'

which the surface Z22 is parallel with the axis of the bar and the surface 3 is curved. The tool holder D has a nose cl at its forwardend which bears'along the surface b2, b3, as theV sleeve is moved forward along thev bar B, and this surface b2, b3, acts as a former to thetool-holder'and insures thatthe tool will bore out Ithe-interior of the `shell to the yshape required, that is to say, parallel' while the a clutch which is revolved within a frame which 4is fixed 'upon l'the machine' bed', in a e 'knownllor any convenient manner; :and ythe rear end ofthe sleeve is fixed to a saddle or 'the-like which is slid'able along they machine bed and is movedtherealong to give lthe required feed lto `the cutter. The-forward end of thev guide bar passes through ai lfixed' suplport-doy which itis 'kept central and in relation to which it is prevented .from moving endwi'sej, and is otherwise kept truly in place by the sleeve. The guide bar may 'be pr`e Vented fromnlovingV endwise' in any lsuitable manner. Conveniently in vthe manner shown by Fig; 5, according'fto which notches fb? -a-re cut in opposite sides `of the bar, with the inner pair of whichl a'key K, at `the in"- ner Vface of fthe support M, through which f the bar passes, is engagedby passingopposite sides of the 'key through thejnotches, and with the outer -pair lof ywhich a key K", atlthe outer face ofthe support, is Isimilarly engaged, the latter Vkeybeing tapered at its outer face, as show-n, to'bear against slanted outer sides ofthe notches and? thus draw the bar yendwise until the key K comes` against lthe inner faceof the support lVf.` A :hole in lthe underside of the sleeve 'mayengage with a stud of the saddle', tov-'insure that, when the boring bar hasbeen' removed and afresh shell has beenL put in place, tfhecorrect posi'- 'tion V'of the ysaddle in relation Vto the sleeve willresultfrorn lowering the underside of 'the sleeve over the stud of the saddle.V Conveniently, the *rear end of the sleeve 1'rests in bearings of the saddle andlis clampeds'domwn thereon, "the stud aforesaid standing f up within onev of such bearings.y IA removable bush N, having abcollar naat `its inner end, and a removable bush N,`-havin'g acollar fn" at its outer end, enable the forward end of the bar to be readily passed through the s upport and its other end to be dropped into the bearings'of the saddle.

The tool E is shown as fixed within the tool-holder by means of a screw F; and a spring G is shown as fixed at one end tothe Y v tool-holder and bearing at its other end against the rearend of the tool, for the purpose of moving the tool outward ysomewhat when the screw F `-h'asbeenslac'kened -fb'ack, and thereby facilitating the removal of; the tool `from the holder; In order to insure that the forwardend of the' vtool-holder will always lbear upon the surface vb2, b3, a spring H which is fixed at' one end to the sleeve bearsagainst a heel of the tool-holder.

The key b, which is slidable `within;the e key-way b'of thebar B, is passed througha slotted opening whichis formedthrough l' the wallof the sleeve, andbesides fitting tightly in such 'slot is fixed lby screwsbf which pass through ears of which lie v'within shallow'extensions ofthe slot, all as is jwell understood. v Y 'f V 56 is a channel for a lubrieatingytubef f The purpose of making the portion of' the guide-bar along which the sleeve is1v sl-idahle eccentricto 'the true 'axis of the complete =appliance is -tofprovide increased spaceforfhe f tool-hold'er'between the guide-'bar andthe interior surface'of the article 'which 1s being bored, and at the same timeallo-,w' the guidebar to be made of such strengththat it will not be unduly7 weakened ati'the point where q the former surface is cut yin'most deeply, and allow the side of the sleeve where the slot is cut to receive the'tool-holderto'be Imade strongerthan could [otherwise be the case. l' L Having fully describedl my invention what I claim and desire to` secureby Letters Patent is n `1. A boring bar comprising a guide'ba-r having a former surface, a sleeve'slidable i on Said guide bar and vheld against rotation thereon,l and a boring`-means pivotally coni lneeted'tosaid sleeve and Yguided lby said former surface of sadbar.

2Q A boring bar comprising a Iguide ybar y having former surface including a straight portion parallel to' the axis thereof and a curved lportioncoi'itinuous -withaid straight portion, a sleeve slidable `on said guidata and heid aggressione@ themen, fr

and boring means Api'votally v@connected'to saidy sleeve and guided: by said;""fo'rmeri7 surface o'f'sraidibar. y

' 3. 'A boflng bar comprising aguide vbar 'provided with a formerf surface, ,a-'sleeve 'slidable' on saidl guide 4'bar land held kagainst rotation thereon, a tool holde'r pivotally con'- nect'ed to said sleeve andv guided'by said e former surface of said bar, anda boring tool carried bylsaid tool holder.l

4. A 'boring barcomprising a.V guide'bar having an eccentric body provided With al former surface, a sleeve slidable on said eccentric body and held against rotation thereon, anda boring means pivotally connected to said sleeve and guided on said former surface -of said bar.

5. A boring bar comprising a guide bar having an eccentric body provided With a former surface, a sleeve slidable on said eccentric body and held against rotation thereon, said sleeve having an eccentricity in reverse of the eccentricity of said guide bar, and a boring means pivotally connected to said sleeve and guided on said former face of said bar.

6. A boring bar for forming a tapered bore comprising a guide bar having a former surface, a sleeve slidable on said guide bar and held against rotation thereon, and a tool holder pivoted to said sleeve and provided at its forward end With a contact nose adapted to engage said former surface,

tion continuous With said straight portion, `a sleeve slidable on said guide bar and held against rotation thereon, and'a boring means pivotally connected to said sleeve and guided by said former surface of said bar. a

In witness whereof I have hereunto signed my name this 4th day of August 1916, in the presence of tvvo subscribing Witnesses.

HERBERT AUSTIN.

Witnesses ERNEST HARPER, STEPHEN WATEINS.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents. Washington, D. C. 

